Fluid temperature limiting electric cut-out device



NOV. 20, 1934. F. W WERRlNG 1,981,484

FLUID TEMPERATURE LIMITING ELECTRIC CUT-OUT DEVICE l Filed Nov. lO, 1931i 3 Sheets-Sheet l FLUID TEMPERATURE LIMITING ELECTRIC CUT-OUT DEVICE 5Sheets-Sheet 2 Filed NOV. 1Q, 1931 NOV. 20, 1934. F. W 'WERR|NG1,981,484

FLUID TEMPERATURE LIMITING ELECTRIC CUT-OUT DEVICE Filed Nov. 10, 1931 3Sheets-Sheet 3 l #Wwf/145x Patented Nov. 20, 1934 UNITED STATES PATENTOFFICE FLUID TEMPERATURE LIMITING ELECTRIC CUT-OUT DEVICE porationApplication November 10, 1931, Serial No. 574,150

4 Claims.

The subject of my invention is a safety device for water heatersoperated by or with electricity which provides a means whereby uponexcessive temperature of the fluidpassing therethrough an electricswitch is caused to operate. My device consists essentially of a fusibleelement, means for conducting heat to said fusible element, a

member movable upon the melting of said fusible element, a stationarycontact, a movable contact cooperating with said stationary contact, andmeans for stressing said movable contact and said member against saidfusible element.

As a more specific modification my device may include a casing having apassage for iiuid therethrough, `an immersion tube of heat conductivematerial in said passage, a fusible element in said limmersion tube, amember movable upon the melting of said fusible element, a stationarycontact, a movable contact cooperating with said stationary contact, adetachable connection between said member and said movable contact, andmeans for stressing said movable contact and said member against saidfusible element.

For a further exposition of my invention reference may be had to theannexed drawings and specification at the end whereof my invention willbe specifically pointed out and claimed.

In the drawings,

Figure 1 is a plan view of my device with the cover lifted away.

Figure 2 is an elevation of my device with parts broken away.

Figure 3 is a side view of a detail of my device with parts broken away.

Figure 4 is a plan view of a modified form of my device.

Figure 5 is an elevation of the same modification with parts brokenaway.

Figure 6 is a detail view of a portion of the same modification withparts broken away.

Figure 7 is a side View of another modification with parts broken away.

Figure 8 is a side view of yet another modif'lcation with parts in crosssection.

vFigure 9 is a plan view of still another modification.

Figure 10 is a side elevation of the modification shown in Figure 9. n

In the modification of my invention chosen for illustration in Figures1, 2 and 3 of the drawings, my device s shown as consisting of a casing10 which includes a hinged cover 11 attached thereto and a conduit 12having a passage 13 which serves as a conduit for fluid through aportion of the casing. Conduit 12 may be detachably secured to (Cl.20G-142) casing 10. Projecting from casing 10 into conduit 12 I providean immersion tube 15 which may, if desired, be provided with externalscrew threads 16 which serve for the attachment of conduit 1 2.Immersion tube 15 serves as a means for conducting heat to fusibleelement 17 and is connected to casing 12 by screw 14 or other readilydetachable means. Within the immersion tube 15 I provide a fusibleelement 17 shown in the form of a disk of metal having a low meltingpoint. Resting upon disk 17 I provide a member 18 which has a guide 19thereon carried in the upper part of immersion tube 15. Member 18carries at its upper end a head 20, as is best seen in Figure 3, whichmay conveniently -be made of insulating material.

Cooperating with head 20 is a yoke 21 carrying a projection 22 thereonwhich may be received in an indentation in the upper part of head 20.Yoke 21 is pivotally mounted on a pivotal arm 23 which is carried on asuitable pivot 24 in casing 10. Pivotal arm 23 is stressed by a spring25 so that member 18 bears on fusible element 17.

At one side pivotal arm 23 carries fingers 26 which embrace a curvedspring 27 which in turn carries a movable Contact 28. Fingers 26 looselyengage spring 27 to provide for lost motion therebetween. Spring 27 istensioned so that it places stress on member 18 through pivotal arm 23.Contact 28 is connected into circuit to cooperate with either upperstationary contact 29 or lower stationary contact 30. Electric leadwires are connected to stationary contacts 29 and 30 and movable contact28 by means of connections 31, 32 and 33 respectively. Casing 10 isprovided with an outlet 34 to permit the escape of the wires.

In practice my device may be connected so that the conduit 12 forms aportion of the inlet or outlet passage for water to a hot water heater.Should the water or any other fluid passing through the conduit 12 riseto an undesired temperature heat is quickly conducted through theimmersion tube 15 which is made of a metal or other heat conductivematerial. Fusible element 17 melts or softens and permits member 18 tofall under the stresses of spring 25 and curved spring 27, thus movingpivoted arm 23 and with it movable contact 28 out of contact withstationary contact 29 and into contact with stationary contact 30.Pivoted arm 23 may conveniently be made of insulating material as isalso head 20. It desired, one or the other of the stationary contacts 29or 30 may be omitted so that the movable contact 28 serves to make orbreak but a single circuit.

1n Figures 4, 5 and 6 I have disclosed a modified form of my devicehaving a casing 110 having an immersion tube 115 connected thereto inany convenient manner. Immersion tube 115 may project into a conduit(not shown) similar to conduit 12 and carries therein a fusible element117.

A member 118 bears on fusible element 117 and is stressed by a spring125 and by curved springs 128 and 228 in a like manner described inconnection with Figures 1, 2 and 3. Spring 125 bears upon a pivotal arm123 which carries on each side iingers 126 and 226 which in turn embracemovable contacts 128 and 228. Movable contacts 128 and 228 engage intheir upper position with stationary contacts 129 and 229 respectivelybut are shown as being disengaged from a stationary Ycontact in theirlower position although, if` desired, such ya stationary contact may beprovided.

.The operation of this modification is very simi-` `larto that of theabove describedmodication. Heat from a fluid passing about immersiontube 115 is conducted to fusible element 117 which melts or softens soas to permit member 118 to punch or shear therethrough,A This permitsspring 125 to move pivotal arm 123 and to thereby move movable contacts126 and 226. n

In Figure 7 there is disclosed another modication of my device in whichthe immersion tube disclosed in Figure 8 in which the immersion tube 155extends directly into the tank of a water heater or. boiler 154. Theimmersion tube 155 contains the fusible element 157 and is attached toya switch casing 10 which may contain switch elements similar to thosealready described. The immersion tube 155 has on its outer surfacethreads 156 similar to the threads 16 described in connection withFigures 1 to 3, inclusive. By means `of these threads the immersion tubemay be retained in position in the wall of the water heater 154. Theswitch casing 10 may, if desired, be located in a chamber 158 in thewall of the water heater 154.

In Figures 9 and 10 there is described yet another modication of mydevice in which the switch is arranged to open upon the melting orfusing of the fusible element instead of closing. As shown in Figures 9and 10 this modification ,consists of a fusible element 317 which isshown in the formof a pin but which may be a bar, a disk or anyconvenient form. Fusible element 317 maybe received in jaws 312 whichare secured together by a -screw 313er other convenient means to retainthe fusible element therein. Connected to the jaws 312 or retained inthe lower jaw is an immersion rod 315 similar to the immersion tube 15,vdescribed in connection with Fig- Vlires 1 to 3, inclusive, except thatit is solid instead of being hollow. as is the immersion tube 15. Theimmersion rod 315, however, serves as a means for conducting heat to thefusible element v 317, A If desired the immersion rod 315 may have onits outer surface screw threads 316 which may conveniently serve forattaching a casing or t- `.ting 311 which has a fluid passageway 310through it. Threads 316 may serve to screw immersion stressing saidpivoted arm and said member element315 and the parts supported therebyin the manner disclosed in Figure 8. Cooperating with fusible element317 is a pivotally mounted member 323 which is pivoted at 324 and whichcarries or has attached thereto a spring keeper 325 upon which a spring425 bears. At one or both of its sides pivotal arm 323 carries fingers326 and 426 which may respectively embrace curved springs 327 and 427.These springs are tensioned to add their stresses to that of spring 425.Upon pivotal arm 323 curved springs 327 and 427 carry at their cuterends movable contacts 328 and 428 respectively, vthese contacts beingadapted to cooperate with stationary contacts 329 and 429 respectively.If desired one of the curved arms 327 or 427 and the movable contact 328or 428 carried thereby may be omitted. I f desired, the correspondingstationary contact 329. or 429 may be omitted or may be positioned aboveits cooperating movable contact so that upon movement of the movablecontact, circuit will be closed instead of being opened. The operationof this modification is similar to that of the modifications alreadydisclosed. Heat is conducted from the fluid, to which the immersion rod315 is exposed, through ,100 immersion rod 315 to fusible element 317.Upon the application of sufficient heat thefusible element softens ormelts and permits pivotal arm 323 to move under the stresses of springs425, 327 and 427 or such of these Vsprings as are used. Due to themovement of pivotal arm 323 movable contacts 328 and 428 are moved outof or into engagement with their cooperating stationary contacts 329 and429. To reset the device screw 313 is loosened and another fusibleelement is inserted in the jaws 312. v

I do not intend to be limited in the practice of my invention save asthescope of the prior ar-t and of the attached claims may require.

' I claim: V1,15

1. An electric switch adapted to be mounted on a conduit having apassage for iiuid therethrough, a fusible element, a member stressed`against said fusible element, a pivoted arm connected to said member, acurved arm of flexible material forming a movable switch contactconnected to said pivoted arm, and a stationary switch contactcooperating with said movablecontact.

2. An electric switch adapted to be mounted on a conduit having apassage for nuid therethrough, a fusible element, a member stressedagainst said fusible element, said member being formed as a rod bearingon said fusible element, a pivoted arm connected to said member, aspring against said fusible element, a curved arm of` exible materialforming a movable switch contact and connected to said pivoted arm, anda stationary contact cooperating withsaid movable switch contact. 1,35

3. An electricswitch adapted to be mounted on conduit having a passagefor fluid therethrough, a fusible element, a member stressed againstsaid fusible element, said member being formed as a rod bearing on saidfusible element, a pivoted arm connected to said member, a quickdetachable connection between said member and said pivoted arm, a springstressing said pivoted arm and said member against said fusible element,a curved arm of iiexible material forming a movable switch contact andconnected to said pivoted arm, and a stationary contact cooperating withsaid movable switch contact.

4. An electric switch comprising, in combination, stationary means forattachment to the ,150

wires of an electric circuit, a movable switch contact connected to saidmeans, a stationary switch contact co-operating with said movablecontact, a fusible element, a member stressed against said fusibleelement and co-operating with said movable switch contact to actuatesaid movable switch contact when said fusible element melts or softens,

